1. Related Technical Fields
Related technical fields include movement guidance systems, movement guidance devices, movement guidance methods, and computer programs that guide a movement of a movable body based on a guidance route.
2. Related Art
In recent years, many vehicles are mounted with navigation devices that are capable of guiding drivers to easily arrive at desired destinations through travel guidance of a vehicle. The navigation devices here are devices, which can detect a current position of the vehicle using a GPS receiver and the like and acquire map data corresponding to the current position through a storage medium such as a DVD-ROM and a HDD or a network, and display a map on a liquid crystal monitor. Further, the navigation devices are provided with a route search function that searches for an appropriate route from a departure point to a desired destination when the desired destination has been inputted. Thereafter, the navigation devices display a guidance route set based on the search result on a display screen and, if the vehicle approaches a branch point (hereinafter, referred to as a guidance branch point) target for the guidance such as a right turn, a left turn, and the like, provide the guidance using audio or a display screen in order to guide the user to the desired destination. In addition, in recent years, some cellular phones, PDAs (Personal Digital Assistant), personal computers, and the like include the same function as the aforementioned navigation devices. Also, it is possible to provide the guidance for pedestrians or two wheels besides vehicles.
Here, if providing the guidance such as a right turn, a left turn, or the like at the guidance branch point, it is necessary to make the user correctly determine the guidance branch point. Especially, if there is a branch point that is adjacent to the guidance branch point and connected to a road in the same direction (for example, diagonally forward left) as the guidance branch point, in order to avoid that the guidance branch point is misidentified with the branch point, it is important to set an appropriate timing to provide the guidance for guidance branch point. For example, Japanese Patent Application; Publication No. JP-A-10-122893 proposes a technology that, if there is a branch point connected with a road in the same direction as the guidance branch point within a predetermined distance before the guidance branch point, sets the timing to provide the guidance for guidance branch point to a timing to pass the branch point.